Optical Properties and Excited-State Dynamics of Safranin O Monomers and Dimers in Aqueous Solution.

Phenazines, phenoxazines, and phenothiazines are a structurally similar set of compounds that exhibit antibiotic and photocatalytic activity and that have been used as histological stains and optical sensors. Safranin O (SO) is a phenazine that has been found useful to quantify polysaccharides in cartilage and that has been shown to have a unique ability to inhibit ice growth. In both of these applications, the high concentration of SO can lead to aggregation, which can result in drastic changes in optical properties and excited-state dynamics.

Structures of a minimal human CFTR first nucleotide-binding domain as a monomer, head-to-tail homodimer, and pathogenic mutant.

Upon removal of the regulatory insert (RI), the first nucleotide binding domain (NBD1) of human cystic fibrosis transmembrane conductance regulator (CFTR) can be heterologously expressed and purified in a form that remains stable without solubilizing mutations, stabilizing agents or the regulatory extension (RE). This protein, NBD1 387-646(Delta405-436), crystallizes as a homodimer with a head-to-tail association equivalent to the active conformation observed for NBDs from symmetric ATP transporters. The 1.